Linear drives are known which perform longitudinal movements without threaded spindles. They use rack-and-pinion transmissions in which a rack is longitudinally displaced by means of an electric motor by way of transmissions and gears. Drives are also known in which a motor-transmission unit is longitudinally displaced by way of gears on threaded spindles. Coarse-threaded drives are also known in which the longitudinal movements are produced by rotation of a threaded tube. All those drives are very complicated and expensive in terms of structure and require expensive drive components.